Corona

Rendering Quality

Corona Renderer offers both biased and unbiased rendering solution at the user’s discretion. In both cases it delivers predictable, reliable, and physically plausible results with no compromises in quality. Our Forum and Gallery section provide great examples of this.

• Biased and Unbiased Rendering

You can render in a fully unbiased mode and use advanced rendering algorithms like BDPT/VCM to get the most realistic, true-to-life results. Or you can use the defaults, which is a slightly biased solution. This is very close to being unbiased, however it considerably reduces render time and increases flexibility. This is the recommended solution as it works straight out of the box with no setup whatsoever. Even in this mode, Corona will always deliver crisp, realistic results without splotches, interpolation artifacts or any other visual imperfections.

Ease Of Use

Usability is our strongest weapon, as Corona is one of the easiest to learn render engines. Its setup is really as simple as pressing “Render”. Most new users will learn Corona in just one day, and fall in love with it over the next few.

• Easy to Understand

Our mission with Corona Renderer is to liberate users from the technical, unnatural process that rendering was in the past. We are constantly trying to simplify the creative process by removing or hiding any unnecessary technical settings, so artists can focus on their vision. The era of studying manuals and sampling tweaking is over. Just press render and let Corona do its magic.

• Artist Friendly

Corona Renderer was developed in tight cooperation with the artist community. Its creators are former artists as well, so this collective knowledge and experience played a huge role in the design and development. We call this approach A.D.D. – Artist Driven Development.

Flexibility

Corona Renderer is extremely flexible. We understand how important it is to be able to “bend” physical laws to deliver the results your clients expect. So Corona supports numerous reality hacks which allow you to get exactly the effect you desire.

• Flexible Lights

You can make any light source invisible to the camera, as well as invisible to reflections/refractions. Shadows can be turned on/off and specific objects can be included/excluded from receiving illumination from any Corona light. Backplates can be easily created with the invisible to GI option. 3ds Max default lights are fully supported.

• Rayswitcher Material

Rayswitcher material and texture allow a wide range of artistic tweaks when rendering with Corona. Use them to create materials invisible to camera or not affecting GI, to reduce or increase color bleeding, and more.

• Environment Overrides

You can use different environment maps for reflections, refractions and direct visibility from the camera. For example you can use a clear sky HDRI as a light source and a second cloudy HDRI just for reflections and refractions.

• Glass without Caustics

Caustics can be difficult to compute, especially when using path tracing. But in many cases, water or glass look plausible even without caustics, window glass panels being prime examples. Because of this, we have decided to disable caustics by default. This significantly reduces render times, and if caustics are needed they can easily be enabled with the “Caustics” checkbox in Corona material.

Speed

Speed is an important factor in production that cannot be ignored. A usable renderer must always deliver results as fast as possible. That is why we are always looking for ways to cut down parsing and rendering times, without forcing users to buy expensive hardware.

• Speed is Important

In fact, we are obsessed with speed and we like to hunt for milliseconds in our own code. Corona Renderer also proudly uses Intel Embree Ray Tracing Kernels, making the CPU-only Corona as fast as many GPU renderers – but without the memory and flexibility limitations.

Interactive Rendering

Corona Renderer brings you state of the art, fully-featured interactive rendering.

• Interactive Capabilities

You can change materials, lights, and create or adjust geometry while rendering. There is no need to manually restart or update the rendering, as it happens automatically usually within less than a second. It runs completely on the CPU, so it has no limitations and does not require any special hardware.

• Same Results

Our interactive rendering is an integral part of the Corona core. In fact, it shares over 99.9% of the regular renderer code. This means that all features of Corona Renderer are supported, and that the results are exactly the same as with the non-interactive version. You can render motion blur, DOF, create proxies, scatter systems and more, all with instant feedback.

• Compatibility

Because our interactive and regular renderer are almost identical, all types of geometry and proxies are supported. The same goes for all the 3ds Max maps and third party maps. Even the advanced third party plugins such as Itoo Forest Pack work as expected. You can find a full list of supported plugins in the Resources section.

Materials

Our design goal for Corona materials is to make them physically based, yet intuitive, flexible, and easy to set up, without having to tweak unnecessary sampling values or other confusing parameters.

• Material Preview

Material preview uses the same rendering engine as the final frame rendering. The default 3ds Max material preview scene is replaced with a custom, more representative Corona scene, to get the real “What You See Is What You Get” material editor.

• GGX

Corona Renderer uses the GGX microfacet model to deliver realistically looking metals and other glossy materials. This model produces much more plausible results than legacy models such as Blinn, Phong, or Ward. Because of our state of the art implementation, using this model does not incur any speed penalty which is usually present in other microfacet models.

• Material repository

Our resources section contains some high quality materials from well-known artists and companies. The free to use materials are a great way to get started in your Corona endeavors.

Lights

The whole process of creating lights is designed to give artists complete control over their scene, while being fast and intuitive. There are no sampling multipliers, no differences between using light objects and materials, and no need to create artificial fill or dome lights. You can use HDRI, IES files, Sun & Sky system, 3ds Max lights, Corona Lights, or you can turn any mesh object into light simply by assigning to it the Corona Light Material.

• No Sampling Parameters

There are no sampling parameters that you would have to set by trial and error. Lights will always work as expected.

• Corona Lights and Corona Light Material

There is no difference in behavior of Corona Lights and Corona Light Material. Both of them have almost the same options and deliver the same results. So it is up to the artist to use what is more convenient.

• Lights and Rendering Speed

In Corona, there is very little penalization for using mesh lights with high polycount. They will perform as well as low-poly ones with the same shape. Additionally, the version 1.0 improves sampling of directional/IES lights. They now render almost as fast as regular diffuse lights. You can see the improvement in this comparison with the older A6 version:

• No more Dome Lights for HDRI

You do not need to set up any dome light object for HDR image-based rendering. Just put your HDRI into a 3ds Max environment and you are done. There is also no need to put downsampled/blurred versions of the map into a GI override slot – HDRIs in Corona work always fast and without splotches, regardless of resolution or complexity.

• Corona Sky System

Corona Renderer was the first production render engine that implemented the most accurate sky system available today – Hošek-Wilkie sky. It is currently selected as default whenever sun/sky is used.